Conventionally, as a data management method in a storage apparatus, a tiered data management method has been proposed (e.g. PTL 1).
By this tiered data management method, respective storage areas respectively provided by multiple types of storage devices of different performances are managed as respectively different types of storage tiers, and the different storage tiers configure a pool, while a virtual volume is provided to the host computer and, in accordance with a write request to the virtual volume from the host computer, a storage area is dynamically assigned to the relevant virtual volume from the pool, and the write target data is stored in the assigned storage area.
Furthermore, by this tiered data management method thereafter the access frequencies from the host computer for respective data written to the virtual volume are managed, and the data of the high access frequency is migrated to the storage area provided by a high-speed and high-performance storage tier (storage tier composed of storage areas of high-speed and high-performance storage devices) while the data of the low access frequency is migrated to the storage area provided by a low-speed and low-performance storage tier (storage tier composed of storage areas of low-speed and low-performance storage devices).